Installer Authentication error " ... installer has unexpectedly quit"

Question

When I try to install various items I get the message "The application installer has unexpectedly quit." This happens for any application I try to install, including when I try to do a software update. It happens exactly after I type my adminstrator password in the Authenticate screen and click OK. It happens whether I am downloading from the Web, or trying to install from a CD/DVD. My computer is a Lombard PB 400, 256 ram, OS 10.2.8.
The problem began when I tried to install a new version of iTunes and the computer froze in the middle of the install. It also happens when I try to update anything through Software Updater, try to install from an optical drive, and I'm thinking it will happen anywhere that I have an installation authentication requirement. I really don't want to reinstall my whole system and do all the updates, so if anyone knows something else I can try, or can help me pinpoint the problem, I would appreciate it.
Thinking the problem was specific to iTunes I first tried solutions specific to that application, then I broadened my approach to system-wide troubleshooting. I continue to get the error. I have:
1) Downloaded another copy of the iTunes install package
2) Deleted everything iTunes from my computer
3) Put the System>Library>Caches>(something software) folder in the trash and restarted the computer. I took it back out and put it back, but when I restarted it was gone, and I forget the original name of the folder.
4) Repaired disk permissions started from the HD
5) Restarted from the original system install disk, repaired disk and repaired permissions
6) Created and tested a new user with admin permissions
7) Looked at the crash log and this is the first part of what I got (the rest is PPC thread state):
Command: Installer
PID: 437
Exception: EXCBADACCESS (0x0001)
Codes: KERNPROTECTIONFAILURE (0x0002) at 0x0000000c
Thread 0 Crashed:
#0 0x900044e8 in __sfvwrite
#1 0x900044a4 in fputs
#2 0x9105b004 in -[NSInstallerSecurity(Private) _launchRunner]
#3 0x016cd65c in -[Authorization _delayedAuthenticationPanel]
#4 0x97e0cf88 in __NSFireDelayedPerform
#5 0x901631dc in __CFRunLoopDoTimer
#6 0x90148c70 in __CFRunLoopRun
#7 0x90180f04 in CFRunLoopRunSpecific
#8 0x969a3b70 in RunCurrentEventLoopInMode
#9 0x969b3a78 in ReceiveNextEventCommon
#10 0x969dabbc in BlockUntilNextEventMatchingListInMode
#11 0x9308e4cc in _DPSNextEvent
#12 0x930a0824 in -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:]
#13 0x930b23f4 in -[NSApplication run]
#14 0x931605cc in NSApplicationMain
#15 0x0000b66c in main
#16 0x000046cc in _start
#17 0x0000454c in start
G5180d, G4SDTiBook, G4TiBook, G4 AGP, PC 604   Mac OS X (10.2.x)  

Answer 1

Thanks.
I should have mentioned that I have already done the Resolving Permissions as outline on Apple Support pages, but, I went ahead and did the complete sequence as shown on Dr. Smokes.
I decided to stop beating a dead horse and did an Erase and Install of 10.2 again since I did not have anything on there yet. So far, everything is working perfectly. I am doing the Software Updates called for one by one to see if any of those caused the problem.
The only thing I did other than doing all of the updates after the install was to install OS 9.2 for my Classic Environment software and I also installed an HP PSC 1315v All-In-One scanner/printer. I cannot imagine that would have done anything.
I did have some strange issues with Where in the USA is Carmen Sandiego and The Star Fleet Technical manual so I may stay away from them unless I start in OS 9 if none of the other updates cause any issues.
Thanks. BTW, How should I rate your answer? I know that it did not solve my problem, but, it is likely that something else I did whacked something.
I'll update when I know more.